Sound changeover systems



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Nov. 1, 1955 J. F. BYRD ET AL 2972257@ SOUND CHANGEOVER SYSTEMS Filed May 25, 1953 2 Sheets-Sheet 2 ATTORNEY United States Patent O SOUND CHAN GEOVER SYSTEMS John F. Byrd, Ashland, and James D. Phyfe, Moorestown, N. J., assignors to Radio Corporation of America, a corporation of Delaware Application May 25, 1953, Serial No. 357,288

11 Claims. (Cl. 179-1003) This invention relates to sound motion picture projection equipment, and particularly to the sound changeover portions of such systems.

In Phyfe U. S. Patent No. 2,440,184 of April 20, 1948, a combination picture and sound changeover system is disclosed and claimed, this system using the exciter lamps for the sound changeover along with interlocking relays. In most prior systems using three projectors, the changeover for the exciter lamps required pre-selecting any two for operation, while the third equipment had to be pre-set by a separate switch. The present invention permits any sequence of operation or selection of projectors without any pre-setting.

One of the important features of the present invention is that a separate exciter lamp supply is used, the capacity of which may be only that required for one exciter lamp. It is well-known that preheating the exciter lamp is desirable, as disclosed in Collins U. S. Patent No. 2,274,529 of February 24, 1942. However, in prior lamp preheating systems, the lamp remained at less than full heat for over long periods of time. This was wasteful of energy and equipment. The present invention is designed to preheat the lamp only during the period between the time the motor cue is observed and the time the picture changeover cue appears. This time interval is in the neighborhood of eight seconds, which is sufficient to permit the lamp to be fully effective when actually fully energized. Another feature is that this preheating of the lamp is accomplished automatically when the motor switch is actuated, thus eliminating human errors.

The system is particularly simple and economical to manufacture and install, and requires the minimum of equipment. The preferred embodiment of the invention utilizes energy from the motor source to preheat the exciter lamp, which permits a very inexpensive direct current lamp supply to be used. If, however, a well regulated direct current exciter lamp supply is available and can be used, the preheat energy may be derived from the exciter lamp supply itself, which eliminates further equipment.

The principal object of the invention, therefore, is to facilitate changing over sound from one sound motion picture projector to another.

Another object of the invention is to provide a simple and economical sound changeover system.

A further object of the invention is to provide a motion picture sound changeover system in which the exciter lamp of the incoming projector is automatically preheated for a predetermined time interval and in which the selection of any projector can be made without pre-setting.

Although the novel features which are believed to be characteristic of this invention will be pointed out with particularity in the appended claims, the manner of its organization and the mode of its operation will be better understood by referring to the following description, read in conjunction with the accompanying drawings, forming a part hereof, in which:

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Fig. l is a schematic circuit diagram of one embodiment of the invention, and

Fig. 2 is a schematic circuit diagram of a modification of the circuit shown in Fig. 1.

Referring now to the drawings, in which the same numerals identify like elements, a regular 11S-volt alternating current supply is connected to conductors 5. This supply provides motor power and preheating energy for the exciter lamps of the system. The circuit of the invention is illustrated for three sound motion picture projector equipments, but is also applicable to more than three. In the present drawings, projector No. l is shown at 6 with its motor 7 and exciter lamp 8. Projector No. 2 is shown at 10 with its motor 11 and exciter lamp 12, while projector No. 3 is shown at 14 with its motor 15 and exciter lamp 16.

In the control box No. 1 for projector No. l, shown at 1S, is a momentary changeover switch 19 with its actuating element 20. This control box also includes a latching relay 22 with its actuating solenoid 23 and its release solenoid 24. A motor and preheat switch is shown at 26 with a preheat transformer 27. In control box No. 2, shown at 29, is the momentary changeover switch 30 with its actuating element 31, and a latching relay 33 with its actuating solenoid 34 and release solenoid 35. The switch for motor 11 is shown at 37, and a preheat transformer is shown at 38. In control box No. 3, shown at 40, is a momentary changeover switch 41 with its actuating element 42 and latching relay 44 with its actuating solenoid 45 and its release solenoid 46. This control box also has a motor switch 47 and preheat transformer 48. A direct current exciter lamp supply of ten volts is shown at 50.

To describe the operation of the system, it is assumed that projector No. 3 is running and it is desired to change over to projector No. l. When the motor cue appears, the operator closes switch 26, which energizes motor 7 over one of conductors 5, conductor 52, switch 26, conductor 53, motor 7, and conductor 54. Simultaneously, over conductor 52, switch 26, and conductor 56, energy is impressed on the primary of transformer 27. This energy is applied to the exciter lamp 8 over the secondary of transformer 27, conductor 57, closed contact 58, conductor 60, lamp 8, conductor 61, conductor 62, and conductor 63. The energy thus applied to lamp 8 will energize it to just a perceptible cherry red, which is sufficient to permit the lamp to come up to full brilliance almost instantly, but insufficient to generate a signal.

Now, when the changeover cue is observed by the operator, he presses element 20 of switch 19, which will energize relay releasing solenoid 46 in control box No. 3. The energizing circuit for solenoid 46 is over one of conductors 5, conductor 65, solenoid 46, conductor 66, closed contacts 67, conductor 69, closed contacts 70, and conductor 71. The latching relay 44 is thereby released and the energy formerly supplied from source 50 over conductor 73, closed contacts 74, conductor 75, conductor 77, conductor 61, and conductor 78 is, therefore, removed from lamp 16. Simultaneously with the releasing of relay 44, the latching relay 22 is actuated by the energizing of solenoid 23 over a circuit including one of conductors 5, conductor 80, conductor 81, solenoid 23, conductor 82, bridged contact 83, and one contact 70 of jumper 84, and conductor 71. The closing of latching relay 22 applies energy from the lamp supply 50 over conductor 85, closed contact 86, conductor 60, lamp 8, conductor 61, and conductor 78. The making of contact 86 breaks contact 58, thus removing the energy from the exciter lamp 8 ob tained from transformer 27. The operator now opens switch 47 in control box 40 to de-energize motor 15.

The above system, therefore, utilizes some of the power from the motor power source to preheat the incoming exciter lamp during the interval between the appearances of the motor cue and the changeover cue, which is in the neighborhood of eight seconds, and which time interval heats the lamp suiciently before it is fully energized from the direct current supply source. It will be observed that the lamp supply 50 may thus have a capacity suflcient for only one exciter lamp and that any one of the projectors 6, 10, or 14 may be selected without pre-setting any switches before the actual operation of the motor switch. Upon operation of any motor switch, the associated exciter lamp is automatically preheated before operation of the changeover switch. The changeover to projector No. 2 is accomplished in the same manner over its respective circuits.

Referring now to Fig. 2, the same projection equipments 6, and 14 are shown together with the same changeover switches 19, 30, and 41 with their respective actuating elements 20, 31, and 42. In this modification of the sound changeover system, however, the latching relays 22, 33, and 44 are provided with an additional swinger and cooperating contacts. As mentioned above, this modification may be used where the direct current exciter lamp supply 90 has a better regulation than the lamp supply 50 in Fig. l. lt is also to be noted that the motor switches 91, 92, and 93 are two-poled, the preheating now being provided solely from the direct current supply 90.

To explain the operation of the circuit in Fig. 2, we again assume that projector No. 3 is operating and that it is desired to change over to projector No. l. The exciter lamp 16 in projector No. 3 is fully energized from supply 90, over conductor 95, closed contact 96, conductor 97, lamp 16, conductor 98, and conductor 99. The contact 96 and a contact 101 are held closed by the relay latch. As soon as the motor cue appears, the operator will close switch 91 in control box No. l, which will energize lamp 8 over a circuit from supply 90, conductor 95, conductor 103, a resistor 104, closed lower Contact of switch 91, conductor 106, closed contact 107, conductor 108, lamp 8, and conductor 99. The lamp 8 will thus be partially energized and preheated. The motor 7 is, of course, energized over the circuit described for Fig. l, but over the upper contact of switch 91.

Now, when the changeover cue arrives, the element 20 of switch 19 is actuated, which energizes the release solenoid 46 of relay 44 over a circuit from one of conductor 5, conductor 110, solenoid 46, conductor 111, closed contacts 112, conductor 113, and closed contacts 114. Thus, the supply 90 will be disconnected from exciter lamp 16 by the opening of contact 96. Simultaneously, the

solenoid 23 of relay 22 will be energized over a circuit from one of conductors 5, conductor 116, solenoid 23, conductor 117, contact 119, jumper 121), one of contacts 114, and conductor 121. The energization of solenoid 23 will break contact 107, removing the energy to the lamp 8 over resistor 104 and closing contact 123 to supply full energy to the lamp 8 from the supply 90 over conductor 124, closed contact 123, conductor 10S, lamp 8, and conductor 99. The relay 22 then locks itself in position and the momentary switch 19 may be released to assume the position shown in the drawing. The manual motor switch 93 is then opened to remove the power from the motor in projector No. 3.

It is observed that the two systems shown in Figs. 1 and 2 operate in substantially the same manner, except that by providing the preheating energy from the large motor power source, the direct current exciter lamp supply 50 is not required to have as good a regulation as direct current exciter lamp supply 90, which supplies full energy to one exciter lamp and preheat energy to another exciter lamp over a period of approximately eight seconds. However, a better regulated power source eliminates transformers 27, 38, and 48. ticular projector may be selected without the pre-setting of any switches.

In either system, any par- We claim:

1. A sound changeover system comprising a plurality of sound reproducers each having an exciter lamp, a motor, a motor switch and a changeover switch, a motor power source, means for connecting said motor power source to each of said motors upon actuation of its associated motor switch, an exciter lamp power source, means for connecting said lamp power source to each of said exciter lamps upon actuation of its associated changeover switch, the motor switch actuated to connect a certain motor to said motor power source simultaneously serving to connect energy to the exciter lamp associated with said motor, and means for limiting the energy supplied to a particular exciter lamp to less than that required for normal operation of said lamp.

2. A sound changeover system in accordance with claim 1, in which connections are provided between said motor power source, said last mentioned lamp, and said last mentioned motor switch for supplying said energy from said motor power source for a period between the actuation of said last mentioned motor switch and the changeover switch associated therewith.

3. A sound changeover system in accordance with claim l, in which said last-mentioned means includes a resistor together with connections between said lamp power source, said last mentioned lamp, and said last mentioned power switch for supplying said energy from said lamp power source between the actuation of said last mentioned motor switch and the changeover switch associated therewith.

4. A sound changeover system in accordance with claim 1, in which latching relays corresponding in number to the number of said reproducers are provided, said relays being released by any other changeover switch, each changeover switch simultaneously actuating its associated relay.

5. A system for changing sound reproduction from one to another of a plurality of sound reproducers cornprising an exciter lamp for each reproducer, a source of energy, means for connecting the full output of said energy source to any one of said lamps at any one time, a motor for each of said reproducers, a motor power source, means for connecting said motor power source to said motors, said last mentioned means including a motor switch, and a changeover switch for each of said reproducers, said changeover switches being included in said rst mentioned means, said motor switches when closed sen/ing to connect their respectively associated motors to said motor power source, means for partially energizing the respective exciter lamps associated therewith from said motor power source.

6. A system in accordance with claim 5, in which said last-mentioned means for partially energizing said lamps from said energy source includes a plurality of transformers each interconnecting said motor power source and a respective one of said lamps.

7. A system in accordance with claim 5, in which means are provided for disconnecting said transformers from said motor power source for partially energizing said lamps and connecting said lamps to said source of energy.

8. A sound changeover system comprising a plurality of sound reproducers, each reproducer including a motor and an exciter lamp, a lamp energy source, a motor power source, a control box for each of said reproducers, said control box including a changeover switch, a relay, a motor switch, and means for impressing less than normal heating energy on any one of said exciter lamps, a circuit including said motor power source, one of said motors, and its associated switch for energizing the associated one of said motors when said associated switch is closed, a circuit including one of said power sources, said lamp, said associated motor switch, and said last-mentioned means for partially energizing said lamp from said power source when said switch is closed, a circuit includng said lamp, said lamp energy source, and a zrst associated one of said relays for fully energizing said lamp from said lamp energy source when said first associated relay is actuated, and a circuit including said motor power source, one of said changeover switches, and a second associated one of said relays for actuating said ciated relay when said last named changeover switch is closed.

9. A sound changeover system in accordance with clairn 8, in which each relay has a. setting solenoid and a releasing solenoid, the changeover switch for one r ducer being connected to the releasing solenoids of the other relays of the other reproducers, and the changeover switch of each reproducer being connected to the setting solenoids of its associated relay.

10. A sound changeover system in accordance with claim 8, in which said means for impressing less than normal heating energy on any one of said lamps is a resistor connected between said lamp energy source and one of said lamps when the associated motor switch is closed.

ll. A sound changeover system in accordance with claim i3, in which said means for impressing less than normai heating energy on any one or" said exciter lamps in a transformer in each of said control boxes, each transformer having a secondary winding connected to its associated lamp, each of said motor switches connecting the primary winding of its associated transformer to said motor power source when it is closed.

Pritchard Sept. 11, 1934 Collins Feb. 24, 1942 

